Rafael Gonzalez, Alan Alonso, Carlos Cruz and Douglas Tomlinson
Rafael Gonzalez, MSc Student, University of Alberta, 9211-116th St., Edmonton, AB, Canada, rafaelde@ualberta.ca
Alan Alonso, PhD Student, University of Alberta, 9211-116th St., Edmonton, AB, Canada, alonsori@ualberta.ca
Carlos Cruz, Associate Professor, University of Alberta, 9211-116th St., Edmonton, AB, Canada, cruznogu@ualberta.ca
Douglas Tomlinson, Assistant Professor, University of Alberta, 9211-116th St., Edmonton, AB, Canada, dtomlins@ualberta.ca
ABSTRACT
Single-storey Slender Masonry Walls (SMW) with low axial loads are commonly built in Canada. Provisions in the Canadian masonry standard CSA S304-14 require walls with a slenderness ratio of 30, or greater, to satisfy several stringent requirements. The reason for these restrictions is that slender walls are susceptible to second-order (P-Delta) effects and instability issues. Some simple solutions exist to reduce this problem, such as increasing steel reinforcement ratios and increasing the rebar depth relative to the compressive face of the wall section. These changes result in stiffer walls which reduce second-order effects, without the use of thicker and heavier CMUs (Concrete Masonry Units). However, recommendations on clear spacing and ductility behaviour provided in Canadian standards prevent, to some extent, the use of these solutions. With the use of an OpenSEES computer model, this study presents a parametric analysis of SMWs to understand their response when changing parameters such as the reinforcement arrangement and the materials strength. The results showed that increasing reinforcement ratio and rebar depth is the most efficient way to stiffen these walls. Three groups of walls with different steel reinforcement ratios ranging from under- to over-reinforced were analyzed. Each group consists of four sections with different steel reinforcement depth. From all these analyses, the authors present a promising solution to the previously mentioned issues, and propose further discussion to determine if code provisions are overly conservative and prevent engineers from designing more efficient configurations.
KEYWORDS: analytical simulation, finite element, masonry walls, out of plane, slender walls
